FRP Shear Connectors for Concrete Wall Panels
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Solution Overview
Problem
Existing connectors for concrete sandwich and double wall panels require metal components, which suffer from thermal conductivity issues and corrosion, and often necessitate additional insulation to fill voids left by connectors, complicating installation and increasing costs.
Innovation Solution
A shear connector system comprising load transfer members made of thermally nonconductive fiber-reinforced polymer, which span insulation layers or air voids, and a retention housing made of rigid insulation to eliminate the need for additional insulation and reduce reliance on metal components, allowing for adjustable positioning and easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal connectors are used to connect concrete wythes through insulation layers, then load transfer capacity is improved, but thermal conductivity increases and corrosion resistance deteriorates
Solution Approach 1:
The patent employs fiber-reinforced polymer (FRP) composite material for connectors, combining high-strength fibers (glass, carbon, or aramid) with a polymer matrix. This composite structure achieves metal-level tensile strength (up to 5000 psi) while maintaining thermal non-conductivity and corrosion resistance, directly resolving the contradiction between load transfer capacity and thermal/corrosion performance.
Solution Approach 2:
The invention changes the material parameters of connectors from metallic to polymeric composite, fundamentally altering thermal conductivity (from high to low) and chemical stability (from corrosive to corrosion-resistant) while maintaining or enhancing mechanical strength through fiber reinforcement.
2Strength
If connectors are installed through insulation layers, then load transfer between components is achieved, but voids are created requiring additional insulation material and complicating installation
Solution Approach 1:
The connector is designed as a pre-assembled unit with the insulation plug already integrated into its structure. This segmentation of functions (load transfer + insulation filling) into a single component eliminates the need for separate insulation materials and simplifies installation to a single-step process.
Solution Approach 2:
The invention merges the connector element and the insulation plug into a single integrated load transfer device. The plug is permanently attached to the connector, combining the load transfer function and the void-filling insulation function into one component that is installed as a single unit.
3Loss of energy
If thicker insulation layers are used to increase energy savings, then thermal performance is improved, but more or stronger connectors are required
Solution Approach 1:
The fiber-reinforced polymer composite material provides exceptionally high tensile strength (up to 5000 psi) that can accommodate increased load transfer requirements of thicker insulation assemblies without requiring additional connectors or stronger hardware.
Solution Approach 2:
The angled configuration of the FRP connectors (typically 45-60 degrees from the panel face) optimizes the distribution of loads across the insulation thickness, allowing the connectors to efficiently transfer loads through thicker insulation layers by leveraging geometric mechanics rather than relying solely on material strength.
Data Source
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AI summary
A load transfer device is provided to connect concrete elements including, but not limited to, sandwich and double wall panel wythes, roof, floor, balcony and canopy members, and pavement. The device may be used to connect and transfer loads between the components of sandwich and double wall panels. The device includes two load transfer members positioned at an angle with respect to one another. Additionally provided are a retention housing for retaining one or more load transfer members at their angled positions and a depth locating means for retaining one or more load transfer members at their proper depth. Also provided are sandwich wall panels and double wall panels employing the load transfer device and methods for manufacturing sandwich wall panels and double wall panels employing the disclosed load transfer device.